The small board you're asking about is not involved... it's the "surge board" for the Intellichlor. The surge board converts an AC input to DC to run the Intellichlor, and also has a sort of comm port expander that adds 2 more "parallel connections" to the Easytouch. You connect the Easytouch comm port to one of the three ports on the surge board and it will 1. connect the Intellichlor to the comm port and 2. give you 2 extra "ports" that you can use to connect other stuff like an indoor remote, pump, or transceiver.